What oil to use in Mercury Cyclone? 429CJ

[brentalan]

There are so many opinions and factors involved, it's hard to figure out which oil to use in this car. I prefer to use synthetic, so I came to the conclusion that M1 15W-50 was best. I have read that these old big blocks have a lot of clearance and 15W-50 has elevated ZDDP levels.

I tried it out and my oil pressure is really high, cruising shows around 80 psi and for some reason it spikes past 90 occasionally. Idle is still like 50 PSI. I changed it out for some M1 High Mileage 10W-40 and it seems to have dropped about 10 PSI. Still, that seems a little high and this oil has less ZDDP than the 15W-50.

Should I try M1 racing 0W-30? It has the elevated ZDDP and might get my oil pressure to stay between 60-80 when cruising instead of spiking. Maybe there is something else going on here with the oil pump? I'm just worried about running a 0w30 with the looser bearing clearances.

 

[Drew99GT]

Rotella T5 synthetic blend 10w30 would be about as close to perfect for your old Merc as you could get. It's a heavy duty oil with high zinc levels.

 

[brentalan]

Thanks Drew, accidentally posted that before I finished typing so I had to edit it to complete the thought. Your recommendation sounds like a good one though!

 

[HangerHarley]

It is true that 15W-50 Anything gives high Oil Pressure levels.

Same drop in pressure when using 10W-40 in my engine. And its a completely different Engine!

Oil pressure aside (Check the Gauge? Sludge monster? Sludge around Sending Unit? Same concerns on my parked car,) id like to see what color an HDEO turns after a time. So thats a vote for the Rotella.

WM had a 2.5 GALLON (yes, 10 quarts) on sale for $28.50. Id seriously consider that. 15w40.

Pic? Or Mileage? Last time Used, this sounds like its not a Daily Driver?


Oil pressure might be a restricted passageway, hence "Sludge cleaning" recoomendation.

 

[brentalan]

mileage: 105,000 previous owner said he did not have the engine rebuilt since he owned it. He bought it in 1996. I forgot to mention it's a 1970.

I bought it last year and I don't drive it a whole lot, but probably more than he did. I've put 1500 miles on it in the year I've owned it. Sludge is a possibility, I did an engine flush before putting in the 10-40 and I attribute the drop in pressure more to the 10-40 than the flush.

I checked the pressure gauge with another, the readings are the same. Haven't checked the sending unit though.

 

[04SE]

If you decide to run Rotella 15w40, Tractor Supply has the same 2.5 gallon jugs on sale for $25.99 until September 15, I believe. It is definitely sometime in mid-late September. We are stocking up for our trucks and tractors.

 

[OVERKILL]

Delvac 1 5w40 would be my choice.

 

[Steve S]

You really do not need a syn in that engine. 15w40 would be a good starting visc for the engine . When I ran big block Chevs hotrodded the 15w40 would give about 80 to 85 psi cold then after running a while the oil warmed up and the psi dropped to 55 to 65 psi and upon teardown and inspection the bearings always looked good. If you run in the winter a 10w30 HDEO could be better. Nice car by the way! Big blocks are cool!

 

[flanso]

I bought the sister to your car in July, 1970; a new Torino 429 Cobra-Jet with the top of the air cleaner protruding through the hood. I ran GTX 20-50, but that was way back when... Mine was an automatic so it came with a Rochester Quadrajet. I much preferred the Holley carb that came with the 4-speed manual equipped cars so I switched the intake and carb for the Holley. Yours is beautiful; sure wish I still had mine. Is yours an automatic?

 

[spasm3]

wow beautiful car!!!

 

[brentalan]

Thanks for all the kind words guys

Mine has the vacuum-operated ram-air, it doesn't protrude like the Torino but air is pulled in through the black vent you see on the hood.

I've got the 4-speed top-loader with the Hurst shifter, no automatic.

The carb is a Q-jet like you had. The Holley only came on the super cobra jet cars as far as I know.

 

[rclint]

I would run a HDEO for sure in that engine, you decide which one Rotella 5w-40 synthetic is an outstanding oil, the best I used of off the shelf local to me oils ( no Mobil HDEO synthetic local).. The 15w40 is also a fine oil !! with the 10w30 not being out (all Rotella products I have used have been outstanding) Delo is also a outstanding HDEO to me these two engine oils run head to head in the heavy duty engine oil. This is with a 5.9 L Cummins Turbo Diesel

Many times people will say how older engines were made with less precision than that of today, and in one way they are correct but don't think that makes older engines sloppy as they are not... engine specifications have not changed much in the years even way way back to the 50's and probably earlier.. Bearing tolerance, and clearance has not changed any to my knowledge while you can purchase very high precision bearings (ball bearings) you will pay huge amounts of money for them... as well engine internals can be confusing as to what is a bearing etc etc..

What is the recommended viscosity from the owners manual (or by the owners manual) for your car/engine... That is a nice car, I have driven a few big blocks I love how they make power all down low from the ones used... You can sure feel them pull hard I guess that's the seat of the pants torque !!

 

[brentalan]

I don't have the original owners manual to the car, I've done searching on some other sites and found conflicting information on what it might be. I think most cars from the era were spec'd 10-40, so that's my guess.

 

[brentalan]

OK, I do have the shop manual and I found these specs:

Motor Oil
Part name: 6000-Mile Motor Oil MS Sequence tested Long Life
Super_Premium_Motor Oil

Ford Part No.: C5AZ-19579-D, E, K, L M, PS

Ford Specifications: ESE-M2C1O1-B


A quick Google search of the part number and specifications came up with some interesting pictures and some specs but seems inconclusive.

 

[aquariuscsm]

I bet a good racing oil like VR1 or Pennzoil GT would be perfect for any 60s-70s muscle car.

 

[brentalan]

Yeah, I was considering racing oil. There is the Mobil1 0w30 and 0W-50, I was thinking the 0w-50 might continue the high oil pressure but worried that 0w30 might be too thin.

I saw the Roush Valvoline oil is on sale on JCWhitney, but it appears to be similar choice - 5w30 and 5W-50.

 

[addyguy]

That is a really, really nice car. Cobra-Jet Torino's and Cyclones are some of my favourite muscle cars!

I know I'm always recommending this, but have you ever heard of Brad-Penn 'Penngrade 1' HP oils? They are MADE for this kind of stuff - I'd run P1 10W-40 if that were my car.

 

[mechtech2]

Rare back then, and of course much more so now!
That oil pressure is pretty high for a 100k +, 40+ year old engine.
I suspect a fault in the measuring system. Since you checked the gauge, a sending unit or high voltage in it [ maybe regulated voltage] may be problems.
Get that straightened out for sure, then decide on your oil.
Expect some use! 600-1,200 miles can be normal consumption.

 

[Nickdfresh]

I'd try Mobil 1 10w30 High Mileage...

 

[brentalan]

I do get some use, a quart every 600 miles just like you said, of course, 600 miles is a few months so a little is probably leaking too.